*3.2. Influence of the Nanolayer Period* λ *on the Cluster and Hierarchical Coating Structure*

The study was focused on the influence of such an important coating parameter as the nanolayer period λ on a cluster and hierarchical structure using an example of the Ti–TiN–(Ti,Cr,Al)N coating with a nanostructured wear-resistant layer (Figure 8). For a coating with λ = 10 nm (Figure 8a), there is a formation of hierarchical feather-like structures, modeled and described, in particular, in [19,20,24–26] for various techniques of the coating deposition. While a coating is being deposited, there in an obvious increase in the cluster size. The studies conducted earlier [52,54,55] also detected an increase in grain size. With an increase in the nanolayer period up to λ = 38 nm (Figure 8b), the feather-like structure becomes less pronounced, and at λ = 160 nm (Figure 8c), no grain growth is detected with an increase in the coating thickness, while the deposition of a coating begins "from scratch" within each nanolayer period. No feather-like structure was also detected for a coating with an extremely long nanolayer period (λ = 1100 nm, Figure 8d). A column structure, without any noticeable increase in crystal size, is formed inside a nanolayer.

**Figure 8.** Formation of the cluster structure of the Ti–TiN–(Ti,Cr,Al)N coatings depending on the nanolayer period λ. (**a**) λ = 10 nm; (**b**) λ = 38 nm; (**c**) λ = 160 nm; (**d**) λ = 1100 nm.
